LED is an electronic element, which can radiate light when applying electric power. The lighting principle of LED is translating electric power to light energy, that is, doping a minute amount of carriers into a conjunction of P-type side and N-type side and continuously combining the minute amount of carriers with a major amount of carriers to form a LED. To be with the good performance of the LED radiation may need a large amount of pairs of electrons and holes, the space charge layers become narrower when applying a forward biased voltage, and then a major amount of carriers are doped into the P-type side and the N-type side according to Fermi characteristic energy level deviation. Due to that the minute amount of carriers are increased on the P-type side and N-type side, the pairs of electrons and holes located on the P-type side and the N-type side are recombined to release sufficient photons. In the present, the categories of LED generally include GaAa, GaAs1-xPx, and GaP series, etc. Additionally, adding nitrogen atoms to the GaAa, GaAs1-xPx, and GaP series LED also can change the lighting color of these series of LED.
Since the LED has the advantages of lightweight, less volume, low power consumption, and long working life, etc., it is gradually used to replace the conventional light bulbs for wide applications and to approach the aspect of environmental protection. However, the light strength of the LED is controlled by stimulating voltage and has an obvious characteristic of emitting directionality, so the illumination of the light projected from the LED is not uniform enough to be applied as a lighting source of a wide-angle lighting apparatus. Accordingly, in order to provide uniform illumination, a preferred application in prior arts is a fluorescent light served without the characteristic of emitting directionality, as a main lighting source of the lamp assembly. These lamp assemblies are usually fitted with one or more fluorescent lights and controlled by single-shift or multi-shift switches, wherein a triple-shift lamp assembly is the representation of all.
Please refer to FIG. 1, which is a partially-exploded view illustrating a structure of a triple-shift fluorescent lamp assembly provided in accordance with prior arts. As shown in FIG. 1, a triple-shift fluorescent lamp assembly 1 provided in accordance with prior arts includes a base 11, three fluorescent lights 12, a reflector 13, and a lampshade 14.
Two ends of the fluorescent lights 12 are fitted on the base 11 as a shape of “reversed U”. The reflector 13 is provided with a sectional shape of “Y” for separating the fluorescent lights 12 and the lights projected from the fluorescent lights 12. The lampshade 14 is composed of a transparent material and covers the fluorescent lights 12 and the reflector 13.
In practice, the triple-shift fluorescent lamp assembly 1 is usually provided with three starters or one or two mutual-operating starters, and a multi-shift switch, so that the triple-shift fluorescent lamp assembly 1 can optionally trigger one, two or three of the fluorescent lights 12.
However, anybody may ask why the fluorescent lights 12 should be provided in the shape of “reversed U”, and it occupies a larger space and generates more heat. People skilled in relative arts will easily realize that both the two ends of the fluorescent lights 12 must be fitted to the base 11 and connected to pre-arranged circuits, electrons can impact particles, especially the particles of mercury vapor, within the fluorescent lights 12 for generating ultraviolet rays to stimulate fluorescent powder projecting white lights. Thus, the fluorescent lights 12 should be designed in a requirement of extending from one end thereof fitted on the base 11 to the other end also fitted on the base 11. For all possible extending shapes meeting the requirement, the shape of “reversed U” has the shortest extending length and is widely applied by most people skilled in this art. Comparing with the fluorescent lights 12, LED just provides a high-voltage pin and a low-voltage pin on one end thereof and may not need the shape of “reversed U” at all.
While, the electric power consumption of the LED is just one eighth of the incandescent light, and the working life of the LED is fifty to one hundred times of the incandescent light